In recent days, smog has blanketed most of China, with cities like Beijing, Shijiazhuang, and Zhengzhou experiencing severe air pollution levels. PM2.5 has become a buzzword, drawing renewed public attention as major media outlets engage in lively discussions. Health-conscious individuals are devising creative ways to combat PM2.5, including masks, essential oils, and more.
Public Health Network interviewed Mo Xiaoneng, Associate Chief Physician and Director of Respiratory Medicine at the Sixth Affiliated Hospital of Sun Yat-sen University, to offer health strategies during this smog-locked period.
Background:
PM, short for particulate matter, refers to solid or liquid particles suspended in the atmosphere. Particles larger than 10 micrometers can be filtered out by nasal hairs and other organs;Particles between 2.5 and 10 micrometers can be expelled by the body if accidentally inhaled, commonly known as PM10. However, particles smaller than 2.5 micrometers—equivalent to one-tenth the diameter of a human hair—enter the bronchi when inhaled, disrupting lung gas exchange and triggering diseases including asthma, bronchitis, and cardiovascular conditions. These are known as PM2.5.
Can Essential Oils Kill Germs and Reduce Inflammation? Just Pseudoscience Circulating
On the 15th, renowned host and CEO of Lefeng.com, Ms. Jing Li, posted a Weibo urging everyone to spray "essential oil air disinfectants" in their offices, implying that essential oils truly possess germ-killing properties.Coinciding with severe PM2.5 pollution in northern cities, many linked essential oil air sterilization to PM2.5. Regarding this, Director Mo Xiaoneng informed the editor of Public Health Network that current medical research lacks evidence proving essential oils can purify air.Director Mo Xiaoneng believes the inherent efficacy of essential oils remains limited. "Most essential oils can help remove dust and particles from the skin through absorption during massage, building a protective barrier. Certain oils may also exhibit some antibacterial properties."Online sources indicate that in 1955, the American Prescription Manual noted tea tree oil's antibacterial strength was 10-15 times that of carbolic acid. In 1983, the Associated Foodstuff Laboratories of Australia conducted skin disinfection experiments using tea tree oil. Applying the oil to unwashed hands significantly reduced bacterial counts.
While specific essential oils used appropriately can indeed kill bacteria or fungi to some extent, it remains unknown whether essential oils can eliminate PM2.5 particles in the air or kill influenza viruses. Further research and observation are needed.Improper use of essential oils not only fails to kill bacteria but may actually increase infection risks. Regarding claims on social media that essential oils can reduce inflammation in the respiratory tract and alleviate respiratory symptoms, Director Mo Xiaoneng informed Public Health Network editors that simply inhaling vinegar vapor is a more practical approach for achieving such effects. The notion that "essential oils reduce respiratory inflammation" is largely a trend-following, pseudoscientific myth circulating among the public.
For this reason, Director Mo Xiaoneng also advises netizens against applying essential oils directly to masks. As essential oils are airtight substances, they can clog the pores of masks. This forces air to bypass the mask and be inhaled directly through the gaps between the mask and the face, thereby negating the intended respiratory protection.
Choosing masks and air purifiers wisely is essential
Amidst smoggy conditions, dust-filtering and air-purifying products have surged in popularity, with netizens showcasing their mask styles on social media. During such extraordinary times, air purifiers—a favorite among celebrities and affluent households—have also drawn significant attention.The Family Doctor editor, who doesn't own an air purifier, also questions the necessity of these products during Guangzhou's relatively mild days—sunny but without blue skies.
Director Mo Xiaoneng informed the editor that Guangzhou's current air quality remains relatively optimistic, with respiratory clinic visits comparable to usual levels and no significant increase. Regarding mask effectiveness, he emphasized several points:
1) Ordinary masks offer little protection.Even the cotton masks worn by doctors can only filter about 20%-30% of particulate matter. To guard against PM2.5, you need at least the specialized protective masks used during the 2006 avian flu outbreak.
2) Two types of masks are recommended: First, composite masks with four or more layers—including protective, non-woven, filter, and cotton layers—primarily used in construction, chemical, electronics, and furniture industries where harmful pollutants and dust are prevalent. Second, 10- to 18-layer pure cotton masks available at pharmacies, which serve as an emergency alternative when the first type is unavailable and are easily accessible to the public.
3) Wearing masks is only a relative protective measure. To truly combat PM2.5 exposure, the fundamental solution lies in addressing air pollution, boosting our own immunity, and spending more time in well-ventilated, clean environments.
Regarding air purifiers—a somewhat unfamiliar concept to editors—Director Mo Xiaoneng noted that these devices have been around for many years. Households with the means can opt for models with negative ion functionality for enhanced effectiveness. Negative ions neutralize microscopic airborne particles, not only enriching oxygen levels but also purifying the air—explaining why forests, mountain springs, and other natural settings boast exceptionally fresh air.
Masks are external aids—boosting immunity and protecting the environment remain paramount.
Some media outlets note that indoor PM2.5 levels can exceed outdoor standards due to smoking, heating fires, or winter window closures, sometimes surpassing outdoor pollution. This makes indoor air quality a serious concern.Director Mo Xiaoneng believes the root cause—environmental pollution—must be addressed first, followed by ensuring proper ventilation. Amid this nationwide battle against PM2.5, he offers four practical tips:
1) Pay attention to daily habits and boost your body's resistance to become "immune to toxins";
2) During severe pollution episodes, minimize outdoor activities and avoid heavily polluted areas;
3) Implement targeted measures like wearing specialized masks or using air purifiers;
4) Maintain indoor ventilation, reduce smoking, and contribute to environmental protection—air belongs to us all. You can't escape it, for it permeates everywhere.
Expert Profile:
Mo Xiaoneng
Director of Respiratory Medicine, The Sixth Affiliated Hospital of Sun Yat-sen University; MD, Associate Chief Physician, Associate Professor. Member of the Guangdong Respiratory Disease Society and the Guangdong Society for Parenteral and Enteral Nutrition. Primarily engaged in clinical practice, teaching, and research in respiratory medicine.Specializes in diagnosing and treating acute/chronic cough, bronchitis, pneumonia, lung abscess, tuberculosis, emphysema, cor pulmonale, bronchial asthma, bronchiectasis, interstitial lung disease, lung tumors, pneumothorax, and pleural effusion.Expertise in invasive and non-invasive mechanical ventilation techniques, bronchoscopic examination and treatment, and critical care management of respiratory emergencies. Has undertaken 4 provincial-level research projects, co-authored 6 specialized monographs, published over 20 academic papers in national journals, and received one Second Prize in the Chinese Medical Award and one Second Prize in the Provincial Science and Technology Progress Award. Awarded First-Class Merit by Guangdong Province and Guangzhou City in 2003 for outstanding contributions during the SARS epidemic response.